Jet and method of filter manufacture



Aug. 21, 1962 P. GALLAGHER JET AND METHOD OF FILTER MANUFACTURE 2Sheets-Sheet 1 Filed Nov. 12, 1959 TONGUE WRA PPl/VG MA T ER/A L Fig 2Q? G n96 @335 m m w 0 m ROD PRBSURE DROP E 55 q mg: @E ES &

WEIGHT //V R00 PAUL GALLAGHER INVENTOR. BY

M4 T W 2 OF M'Ax sruk'F/L'R JET PRESSURE ATTORNEYS Aug. 21, 1962 P.GALLAGHER 3,

JET AND- METHOD OF FILTER MANUFACTURE Filed Nov. 12, 1959 2 Sheets-Sheet 2 Paul Gallagher INVENTOR.

BY M 9% A! IQRNEYS 3,050,430 JET AND METHOD ()F FILTER MANUFACTURE PaulGallagher, Kingsport, Tenm, assignor to Eastman Kodak Company,Rochester, N.Y., a corporation of- New Jersey Filed Nov. 12, 1959, Ser.No. 852,267 Claims. (Cl. 156166) This invention relates to an improvedmethod and apparatus for forming crimped continuous filament tow intotobacco smoke filters. More particularly, this invention relates to animproved jet for motivating and forming a lower denier per filament,more highly crimped tow than has heretofore been used into filter rodsfor cigarette tips.

As is known in the industry, a substantial amount of filter productionis carried out generally in accordance with the apparatus of the kindshown in Crawford and Stevens US. Patent 2,794,480 and by the methoddisclosed therein. In prior type of operation the filaments to be madeinto filter elements, after the filaments have been opened up, aftertreating with plasticizer and fluifing, are then mechanically pulled ordrawn into the garniture for compacting and forming the preliminarilyprocessed crimped filaments into the filter element. Such prior artmechanical type treatment tends to pull out the crimps and otherwise isnot as eificient as the present invention.

In companion Wexler US. application Serial No. 761; 602, a co-worker hasshown an improved method and jet whereby the spread-out band offilaments may be pushed by gas through filter forming and wrappingmeans.

After extended investigation I have found certain improvements in theWexler method and apparatus for compacting and forming filaments intofilter elements.

This invention has for one object to provide a process of condensing abundle of continuous filaments to a smaller diameter under little or notension whereby a substantial percentage of each filament is positionedmore nearly crosswise to the longitudinal axis of the filament bundle.Still another object is to provide a process of condensing a bundle offilaments to a smaller diameter whereby there is obtained a firmer andmore fully packed filter element than obtainable by prior methods. Stilla further object is to provide a process of condensing a bundle offilaments by means of the aspirating action of air or the like gas in amanner whereby the filaments are pushed rather than pulled into thecompacting mechanism. Still another object is to provide a process ofmaking filter rods particularly adapted for the attachment tocigarettes, which process is relatively simple and more efiicient thanprior art processes. Another object is to provide an apparatus formaking filter elements from continuous filaments, which apparatuscontains an air jet in special combination with forming means. Stillanother object is to provide a specially shaped jet particularly adaptedfor handling a bundle of continuous crimped filaments whereby thefilaments may be motivated but still maintained in a relatively relaxedor untensioned state. Other objects will appear hereinafter.

In the broader aspects of my invention I have found that if a band ofopened-up continuous crimped filaments is pushed rather than pulled ordrawn into the compacting and forming means that substantially betterresults may be obtained. Expressed in another way, I have found that ifthe filaments being made into the filter element are maintained in asomewhat relaxed or untensioned state that a relatively large percentageof each filament may be positioned somewhat crosswise or perpendicularto the longitudinal axis of the filament bundle. Such crosswisepositioning of a portion of the filaments results in a more efiicient orhigher removal filter for a given pressure drop or draw through'thefilter. Thus, by the present invention filters can be produced having a3,050,430 Patented Aug. 21, 1 962 higher removal at the same pressuredrop or equal removal with a lower pressure drop than filters producedby prior art procedures. Furthermore, by the present invention where thefilaments are motivated by air or the like gas in a manner which pushesthe filaments into the compacting and forming means, even though finermore highly crimped filaments are used such filaments are not broken andan improved filter is obtained.

This may be accomplished in the present invention by employing a certainapparatus construction which includes therein a specially shaped jetpositioned in a certain relationship in the apparatus with respect tothe compacting and forming means. The preferred jet of the presentinvention is, as just mentioned, of a special construction whichfacilitates pushing the crimped continuous filament into the formingmeans in an improved manner.

For a further understanding of my invention reference is made to theattached drawing forming a part of the present application.

In the drawing:

FIG. 1 is a semidiagr-ammatic side elevation view of the forminggarniture in combination therewith my novel improved aspirating jet.

FIGS. 2 and 3 are graphs for showing the improvement in filter productwhich may be obtained using the improved jet of the instant invention.

FIG. 4 is a transverse cross section through parts 8 and 9 of FIG. 1.

Reference is made now to FIGS. 1 and 4 wherein the improved jet 6, thetongue 8 and the forming member 9 are shown in longitudinal and crosssections. Certain of these parts, as well as certain other parts, may bethe same as those in Wexler referred to above. However, the jet isdifierent as will be apparent as the description proceeds. It will befurther noted that the wrapping material 16, the endless belt 11, aswell as rollers 15 and 19 may be as shown in Wexler.

let 6 preferably is of cone-shaped constructionf That is, the jetoverall can be considered somewhat as a truncated cone shape therebyhaving a considerably greater cross-section on the entrance end 30 thanon the exit end 31. The jet is made up of the inner member 32 and theouter member 33. These parts are suitably threaded at 34 or otherwisefabricated so that they may be assembled together and provide thechamber 35 which encircles the entire inner member. An opening into thischamber is provided at 36 for the introduction of air or other gas. Theinner walls of this chamber are shaped so as to provide an outletorifice '38 around the periphery of the inner member. 'In other words,this outlet orifice permits the air or the like motivating gas to escapeout through the exit end 31 of the jet. The size of this outlet orificemay be determined by the thickness of the gasket 51.

It will be observed that the jet 6 is suitably positioned at an angle soas to permit the ready movement of the Web of wrapping material 16thereunder as well as the movement of the endless belt 11.

The portion of jet 6 labeled L is an improvement over the Wexler jet. Lis'a diverging or venturi nozzle, with D larger than D made as part ofthe jet. This nozzle takes advantage of the venturi orifice principle bywhich a greater flow of air is obtained compared to a jet with a sharpedge orifice. As referred to above, the aspirating eifect of the jet, aswell as the amount of compressed gas used, is controlled by thethickness of the gasket (which regulates the opening of the orifice) andthe pressure of the compressed As may be noted from the drawing of FIG.1, the inner nozzle isv centered at the orifice by two mating diameters52 midway on the inner and outer nozzles.

The best operation of this improved jet depends on dissipating thevolume of air emerging from the jet so the filaments of the filter toware not blown onto the portion of the wrapping paper that seals thefilter. This may be accomplished by drilling diameter holes 53 in thetongue of the filter forming apparatus on centers not greater than h Itis advisable to drill more holes on the front side of the tongue sincethe sealing edge of the wrapping paper passes along the firont edge ofthe tongue. The stuifer jet should extend under the tongue far enough toinsure no filaments blowing out from under the tongue. It may bedesirable to machine an elliptical recess in the top of the tongue forthe jet, or it is possible for the tongue to be an integral part of thejet. The jet should be located at an angle to the horizontal as shown inthe drawing such that it will be as horizontal as possible withoutinterfering with the movement of the paper or put undue drag on the towas the tow enters the jet from the feed roll.

-In regard to the size of the jet this will be governed to some extentby the size and number of the crimped filaments being supplied thereto.in the present construction where cigarette filters are being made, ajet of about two inches diameter at the entrance end and /8 to inchdiameter at the discharge end is quite satisfactory. That is, such a jetwill handle 5,00030,000 filaments of a size to make a tow of 20,000 to80,000 total denier.

While the air or other gas can be directly introduced into the jetthrough inlet 36, if desired, suitable control valves can beincorporated with the jet to provide the desired control over the volumeand/or pressure of the fluid going into the jet. Rods of difierentlevels of weight and/or pressure drop can be made by changing the rateat which the tow is fed to the jet. By varying the pressure supplied tothe jet, diiferent rates of tow feed can be accommodated by the jet.

The operation of the above described apparatus is thought apparent to asubstantial extent from an inspection of the drawings and considerationof the preceding description. The operation is relatively simple andefiicient but a brief general description will now be set forth.

A band of several thousand continuous crimped filaments is fed intoinlet 30 of the jet. It is relatively easy to feed the filaments to thejet since the gas supplied to the jet causes it to be substantiallyself-threading. By supplying a suitable amount of air to the jet at 36the band of crimped filaments is pushed through the jet and under tongue8 into the forming means 9 where the filaments are compacted and formedinto a cylindrical shaped filter element. At the same time this is beingaccomplished the wrapping material 16 is being continu ously suppliedand the endless belt 11 conveys the wrapped filter rod out of formingmeans 9 to the subsequent steps such as cutting the rod into suitablelengths.

A still further understanding of my invention will be had from aconsideration of the following examples which illustrate the advantagesof the venturi stuifer jet and modified tongue of the present inventionin comparison with the subject matter of the aforementioned companionapplication of Wexler.

Example I Rods were made from D/F70,000 T.D. tension bloomed tow usingboth types of apparatus. Both rods were 24.8 mm. circumference by 90 mm.long. The following data was obtained.

4 Example II Another pair of rods were made from 2.1 D/F-46,000 T.D. airfluifed tow. All conditions were identical except for the stutter jetand tongue.

From the above and other data it may be seen that the instant inventionhas several advantages over the aforementioned Wexler subject matter.

(1) The modified apparatus of the present invention is capable ofattaining the same rod pressures as the Wexler jet with 40 to 50% lesscompressed Likewise, a higher rod pressure is possible with the same airusage. This is a less expensive method due to lower air consumption andalso the same rod pressures are possible with lower pressure airindicating a less expensive source of compressed air.

(2) The modified apparatus of the present invention is easier to operatethan the Wexler jet because it does use less air to obtain equivalent orbetter results. One of the limitations of the stuifer jet is the degreeto which filaments are blown out of the tongue and garniture at the exitof the jet. It is, therefore, apparent that the jet can be operated withless trouble or to higher limits if less air and lower velocities areencountered at the exit of the jet. 7

-(3) The maximum rod pressure is increased with the modified apparatus.The relative increase is independent of rod circumference.

(4) A particularly beneficial use of the modified apparatus of thepresent invention is with the finer D/ F tows, either air bloomed or acombination of air and tension bloomed. However, the apparatus of thepresent invention may be used to advantage on the larger D/ F tows thatare tension bloomed. Therefore, it is possible to use the modifiedapparatus to advantage on all tows from less than 1 D/F to 16 D/F.

(5) Since the removal of a filter is a function of the pressure drop ofthe filter, it is evident that filters with a higher removal arepossible using the present invention.

While in the above examples therewere used relatively moderate airpressures from about 3 to 8 p.s.i.g. for higher speed operation it maybe desirable to increase the air pressure up to 30 p.s.i.g. It will beobserved as indicated above that the instant invention not only operatessatis factorily on finer filaments than heretofore have been commonlyused in filter manufacture such as filaments having a denier perfilament of about 2, but the present invention will also operatesatisfactorily on filaments having a denier of 5 or higher and beingpresent in a total denier of 80,000 or more. Likewise, the presentinvention works satisfactorily on filaments which are crimped withvarious degrees of crimp from, for example, 6 crimps per inch up tocrimps of the order of 40 crimps per inch. \Therefore, the presentinvention will function satisfactorily not only on filaments heretoforeused in the manufacture of filters but will operate successfully on veryfine, highly crimped filaments.

The present invention possesses merit and utility in that it is possibleto increase the weight and pressure drop of the filter by using thisventuri type jet to limits not attainable formerly. An example of thisis that of a 24.8 mm. x mm. rod of SD/F x 70,000 tow being increasedfrom 7.5" to 11.5" pressure drop. This is an increase of 53.4% inpressure drop for the corresponding increase in weight of 11.7%. It ispossible to increase the pressure drop of the finer D/ F tows to beyondpresently used limits in commercial filters. Thus virtually any filterrod pressure drop desirable is easily attained by the use of thisimproved stufier jet in combination with the modified tongue which willrelieve air from the garniture or rod forming apparatus.

The foregoing may be further appreciated by referring to FIGS. 2 and 3of the attached drawing. FIG. 2 assumes any one given tow item and showsthat pressure drop increases at a greater rate than rod weight withgiven increments in stuffer jet pressure. FIG. 3 demonstrates thatpressure drop obtained by increasing the rod weight by stuifing rises ata faster rate than the pressure drop obtained by increasing the rodweight through using higher total denier tow. The shaded area representsthe type improvement obtained through the use of the present invention.These and other related improvements are summarized as follows:

(1) Improved tow utilization in terms of pressure drop per unit rodweight.

(2) Improved hardness at same pressure drop by using lower total denierand stuffing up to desired pressure drop, rather than obtaining desiredpressure drop with total denier increase.

(3) Improved versatility in that rods may be made at more than onepressure drop level, yet only one tow item need be kept in inventory.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effec'ted within the spirit and scope of theinvention as described hereinabove and as defined in the appendedclaims.

I claim:

1. An apparatus for manufacturing filters out of continuous crirnpedfilaments comprising a truncated coneshaped jet with a large and a smallend, said small end being in the form of a venturi leading into tonguecompacting means, means for conducting gas through said jet, means formoving compacted filaments through said tongue compacting means, andmeans for feeding wrapping material in close association with saidtongue compacting means.

2. An apparatus in accordance with clairn 1 wherein the venturi ispositioned at an angle to the tongue compacting means.

3. An apparatus in accordance with claim 1 wherein the large end of thejet is at least 2 inches in diameter and the portion of the venturiadjacent to the tongue compacting means is larger than the opposite endof the venturi.

4. An apparatus for manufacturing filters out of continuous crimpedfilaments comprising a jet in combination with compacting means, saidjet being of a truncated cone shape with a large end and a small endhaving a venturi member adjacent said compacting means, an endless beltleading through said compacting means, means for feeding wrappingmaterial into said compacting means, said compacting means having at theentrance end thereof a tapered portion perforated with a plurality ofholes whereby aspirating gas emerging from said jet is dissipated,thereby preventing said continuous crimped filaments from being blownonto the sealing portion of said wrapping material and causing a looseseal.

5. A method of making filter elements from crimped continuous filamentswhich comprises passing a hand of several thousand filaments into atruncated cone-shaped jet, supplying a gas to said jet whereby saidfilaments are motivated through said jet and upon exiting therefrom arepushed through a venturi nozzle into tongue compacting means, therebybeing formed into filter elements, permitting some of said gas to escapethrough peripheral holes in said tongue compacting means, therebydissipating the gas emerging from said jet and preventing the filameritsfrom being blown onto the sealing portion of a wrapping Web supplied tosaid tongue compacting means whereby the formed filter elements arewrapped, sealing the wrapping web around the filter elements and cuttingthe filter elements to length.

6. The method in accordance with claim 5 wherein the filaments arecellulose acetate filaments of a denier per filament of less than 16.

7. A method in accordance with claim 5 wherein the filaments arecellulose acetate filaments of a denier per filament of less than 3.

8. In a process of manufacturing filter elements from cellulose acetatefilaments wherein the filaments are conducted into compacting meanswhich shape the filaments into filter elements, the improvement whichcomprises passing the filaments through an air jet having a venturisection immediately adjacent said compacting means whereby the filamentsare motivated into said compacting means.

9. The improvement in accordance with claim 8 wherein the air pressureto supply the jet for motivating the filaments is from 2 to 30 psig.

10. In the process of manufacturing filter elements from a band ofseveral thousand continuous crimped filaments, the steps which comprisespreading out the crirnped filaments and then conducting the spread-outfilaments through an air jet ending in a venturi section into acompacting zone and applying air pressure thereto sufficient to motivateand push the filaments through said venturi section into said compactingzone.

References tilted in the file of this patent UNITED STATES PATENTS

1. AN APPARATUS FOR MANUFACTURING FILTERS OUT OF CONTINUOUS CRIMPEDFILAMENTS COMPRISING A TRUNCATED CONESHAPED JET WITH A LARGE AND A SMALLEND, SAID SMALL END BEING IN THE FORM OF A VENTURI LEADING INTO TONGUECOMPACTING MEANS, MEANS FOR CONDUCTING GAS THROUGH SAID JET MEANS FORMOVING COMPACTED FILAMENTS THROUGH SAID TONGUE COMPACTING MEANS, ANDMEANS FOR FEEDING WRAPPING MATERIAL IN CLOSE ASSOCIATION WITH SAIDTONGUE COMPACTING MEANS.